GeS “nanoflowers” could blossom in next-gen solar cells

The GeS "nanoflowers" have petals only 20-30 nanometers thick, and provide a large surface area in a small amount of space

Researchers have already turned to the humble sunflower for inspiration to design more efficient Concentrating Solar Power (CSP) plant layouts, and now a team from North Carolina State University has developed a “nanoflower” structure out of germanium sulfide (GeS) that shows great promise for use in energy-storage devices and more efficient solar cells. The secret is the material's ultrathin petals that provide a large surface area in only a small amount of space.

The researchers created the flower-like structures by first heating GeS powder in a furnace until it began to vaporize. The vapor is then blown into a cooler region of the furnace, where the GeS settles into a layered sheet measuring just 20 to 30 nanometers thick and up to 100 micrometers long. A flower-like structure similar to a carnation or marigold is formed as additional layers are added causing the sheets branch out from one another.

GeS is a semiconductor material that is attractive for use in solar cells because it is inexpensive and non-toxic, while its atomic structure makes it good at absorbing solar energy and converting it into useable power. But solar cells aren’t the only potential applications for the nanoflower technology.

“This could significantly increase the capacity of lithium-ion batteries, for instance, since the thinner structure with larger surface area can hold more lithium ions,” says Dr. Linyou Cao, an assistant professor of materials science and engineering at NC State and co-author of a paper on the research. “By the same token, this GeS flower structure could lead to increased capacity for supercapacitors, which are also used for energy storage.”